As illustrated in FIG. 1, a construction machine according to a conventional art includes: a lower driving structure 1; an upper frame 2 mounted on the lower driving structure 1 to horizontally swivel; a cab 3 mounted on one side of an upper surface of the upper frame 2; a fuel tank 4 installed on one surface of a front part of a side opposite to a side at which the cab 3 of the upper frame 2 is mounted; a hydraulic fluid tank 5 installed to be adjacent to a rear part of the fuel tank 4 of the upper frame 2; and a counterweight 6 installed at a position corresponding to the rearmost part of the upper frame 2; and a working device 10 fixed to one side of a front part of the upper frame 2 and including a boom 7, an arm 8, and a bucket 9 that are operated by respective hydraulic cylinders.
Since a volume of the fuel tank 4 is limited, the fuel tank does not meet the requirements for use in a construction machine in a work condition in which the time of use of the fuel tank is 10 hours or more, namely, in remote areas where working is performed for 2-3 days with one fueling. Due to this, there has been an ongoing demand for solving the lack of a volume of the fuel tank. Further, the absence of a storage space for tools has also been pointed out.
As illustrated in FIG. 2, a construction machine according to another conventional art includes: a lower driving structure 1; an upper frame 2 mounted on the lower driving structure 1 to horizontally swivel; a cab 3 mounted on one side of an upper surface of the upper frame 2; a fuel tank 4 installed on one surface of a front part of a side opposite to a side at which the cab 3 of the upper frame 2 is mounted; a hydraulic fluid tank 5 installed to be adjacent to a rear part of the fuel tank 4 of the upper frame 2; and a counterweight 6 installed at a position corresponding to the rearmost part of the upper frame 2; a working device 10 fixed to one side of a front part of the upper frame 2 and including a boom 7, an arm 8, and a bucket 9 that are operated by respective hydraulic cylinders; and an additional fuel tank 4a installed to be adjacent to a front part of the counterweight 6 of the upper frame 2.
According to the construction machine illustrated in FIG. 2, despite the fact that a volume of the fuel tank can be increased by the fuel tank 4 and the additional fuel tank 4a, inconvenience of the lack of a storage space in which a storage space in which tools required for working can be loaded has not been improved.
In addition, when the fuel tank 4 and the additional fuel tank 4a are installed, since a separate junction tank 11 is used, it is problematic in that corresponding components are added.
Also, since left and right sides of the additional fuel tank 4a are exposed to the outside, it is problematic in that the additional fuel tank 4a can be damaged by coming into contact with an external object during turning work.
In addition, since a fuel injection port (fuel filling hole) of the additional fuel tank 4a is adjacent to a muffler of an engine room, it is problematic in that a fire danger may occur.